Lecture 15

  1. Name the two principle pathways:
    • Dorsal Column meniscal
    • Spinal Thalamic
  2. The typical chain of neurons involves
    First order neuron: The cell body of the afferent neuron in the ____ ____ ____:
    Second order neuron: found in the ____ horn of the spinal cord or the _____ ____.
    Third order neuron: found in the _____.
    • Dorsal Root Ganglion
    • Dorsal or medulla oblongata
    • thalamus
  3. Describe the three main levels of neural integration:
    Level I: The receptor level corresponding tothe sensory receptors– Level II: The circuit level corresponding tothe ascending pathways– Level III: The perceptual levelcorresponding to the awareness of theincoming stimuli
  4. _____ level– Information aboutinternal and externalenvironment _____ level– Ascending pathwaysto the brain
    _____ level– Allows us to beaware of stimuli anddiscriminate abouttheir characteristics
    • Receptor
    • Circuit
    • Perceptual
  5. Organization of Somatosensory System
    ____ ____– Cell body of theafferent neuron in the dorsal root ganglion
    ____ ____– Neuron in the dorsal horn of spinal cord or medulla oblongata
    _____ _____– Neuron in the thalamus
    • First Order
    • Second Order
    • Third Order
  6. _____ _____ _____ neurons: respond to fine touch and pressure and pressure; joint, tendon, and muscle change; and pain and temperature.
    Dorsal-root ganglion neurons
  7. ____ _____ nuclei: relay fine touch and sensations.
    dorsal column nuclei
  8. _____ _____: contains axons that carry sensory info to the ventrolateral thalamus.
    medial leminiscus
  9. _____ _____: relays sensory information to the somatosensory cortex.
    ventrolateral thalamus
  10. _____ _____ tract: receives input from pain and temperature neurons and then joinst hte pathway called the ______ leminiscus.
    • ventral spinothalamic
    • medial leminiscus
  11. Regarding the Dorsal Column
    _____ afferents ascend all the way to the medulla.
    - (ipsilaterally or contralaterally)
    - found in the (ventral or dorsal) portion of the cord
    - pass through the ____ fasciculus (leg) and then through the ____ fasciculus (arm).
    • Primary afferents
    • ipsilaterally
    • dorsal
    • gracile fasciculus (to the gracile nucleus)
    • cuneate fasciculus (to the cuneate nucleus)
  12. Regarding the Dorsal Column
    _____ afferents cross at the medulla.
    - (ascend or descend) at the medial leminiscus
    - synapse at the ______
    - ascend to the ______
    • Secondary
    • ascend
    • thalamus
    • cortex
  13. Regarding the Spinothalamic Tract
    ____ afferents enter spinal cord _____ and pass throught the dorsal horn laminae.
    - laminae I, V- ___ fibers
    - laminae II- ___ fibers
    ____ afferents cross over via the _____ _____.
    _____ afferents ascend via the _____ tract. and synapse at the _____. Final afferents _____ to the cortex.
    • primary
    • laterally
    • A-delta fibers
    • C fibers
    • secondary- ventral commissure
    • secondary
    • spinothalamic
    • thalamus
    • ascend
  14. ______ tract: projects info about painful stimuli to VPL (called the neospinothalamic tract) also projects info to intralaminar nuclei (important for emotion component of pain).
    Spinothalamic tract
  15. ______ tract: transmits sensory info to neurons in reticual formation which then project to intraluminar nuclei (part of paleospinothalamic tract)
    spinoreticular tract
  16. _______ tract: terminates in midbrain, tectum, and periaqeuductal gray, integrates somatic sensation with visual and auditory info.
    spinomesencephalic tract
  17. The ___ ____ fascicle transmits info from leg and lower trunk.
    The ___ ____ fascicle transmits info from the upper trunk and head.
    The two halves of the spinal cord are separated by dorsal ___ ____.
    The cuneate and gracile fascicles are separated by the dorsal ____ ____.
    • medial gracile fascicle
    • lateral cuneate fascicle
    • dorsal median septum
    • dorsal intermediate septum
  18. The organization of the dorsal columns is called _____.
  19. Ascending axons of the spinothalamic system originate in the spinal (gray or white) matter.
    Decussation occurs at the (dorsal or ventral) commissure.
    • gray matter
    • ventral commissure
  20. ____ ____ ____ neurons carry fine touch and pressure info.
    Have (large, small) (myelinated, unmyelinated) axons whose receptors are located in the skin, muscles, and tendons.
    Fine touch and pressure axons, ascend (ipsilaterally, contralaterally) forming the spinothalamic tract to the neocortex.
    • Dorsal Root Ganglion
    • Large, myelinated
    • ipsilaterally
  21. Primary somatic sensory cortex has cytoarchitectonic divisions _, _, __, __.
    Info from deep structures = __, and _ (course representation).
    Info from mechanoreceptors of skin= __ and _.
    Limb position= __ and _.
    Touch perception= __ an _.
    • 1,2,3a,3b
    • 3a and 2
    • 3b and 1
    • 3a and 2
    • 3b and 1
  22. The primary somatic sensory cortex is located in the ____ ____.
    Axons travel from ___ to cortex through (anterior or posterior) limb of ____ ____.
    • postcentral gyrus
    • VPN
    • internal capsule
  23. ______: final stage of sensory processing. Allows us to be aware of stimuli and discriminate about their characteristics.
  24. As sensory info reaches the ____, they are perceived in a crude sense.
  25. The thalamus projects fibers to the ____ _____ cortex.
    primary somatosensory cortex
  26. Because fine touch and pressure sensations are conducted to the brain ipsilaterally though the dorsal column/medial lemniscus system, they are lost (above or below) the level of damage (contralateral or ipsilateral).
    • below
    • ipsilaterally
  27. Because pain and temperature sensations are conducted to the thalamus contralaterally through the thalamus contralaterally thourgh the ventral spinaothalamic tract, they are lost (above or below) the level of damage (ipsilaterally or contralaterlly)
    • below
    • contralaterally
  28. Where would sensation be lost if Left gracile fasciculus were damaged.
    left leg and lower left trunk
  29. What would be lost if left dorsal column (both gracile and cuneate fasciculi) were damaged?
    left side of body below level of cut
  30. What would be lost if right medial lemniscus in the medulla were damaged?
    entire left body from neck down
  31. Three key sensory deficits that follow spinal cord injury permit localization of trauma. Describe.
    • Sensory modality that is affected
    • Laterality where deficit is observed
    • body regions affected
  32. _____ _____ Syndrome: damage to one half of spinal cord. Deficits in touch and limb position sense are ipsilateral. Deficits in pain and temperature are contralateral. Injury is at level of most rostral dermatorme where tactile sensation is impaired and few segments higher than the most rostral dermatome where pain is impaired.
    Brown-sequard syndrome
  33. _____ ____: advanced syphilis, large diameter axons last, damage of DCML lemniscal system.
    tabes dorsalis
  34. _______: a cavity forms in the central portion of the spinal cord, destroys axons of AL decussating at ventral commisure, only affects level of lesion, everything below is OK.
Card Set
Lecture 15
Lecture 15